In the U.S., chronic sinusits is associated with over 40 million visits to physicians and health care providers each year. Sinusitis is diagnosed based on clinical history which is difficult to correctly ascertain, and hence misdiagnosis leads to both over-treatment (i.e. antibiotics) and under-treatment (i.e. misdiagnosis as allergies or migraine). Praxis Biosciences, LLC aims to develop and deliver a very low-cost optical imaging tool for quick and simple assessment of sinusitis suitable for use by both primary care doctors and physician extenders. In this proposal, we will first improve on the design of a novel validated prototype developed at the Beckman Laser Institute at UC Irvine by optimizing device form factor, robustness, and optical design. Our device is based upon the principles of near-infrared (NIR) trans-illumination but exploits the unique near infrared optical properties of living tissue to generate substantially greater signal yield. In the second phase of the fast-track, we will validate its efficacy of this market-ready optimized device via a clinical study with Ear, Nose & Throat (ENT) specialists and primary care physicians. The proposed low-cost optical imaging tool will be able to provide means to better identify patients with acute sinusitis and then monitor the response to therapy in primary care settings. Ultimately, our device will help reduce the health-care costs related by optimizing and streamlining diagnosis and treatment.